The study, published in Gastroenterology is a follow-up a previous paper published in Science that suggested altered gut microbiota may play a role in promoting metabolic syndrome.
Now, using an improved technique the team have reaffirmed their findings in a ‘more significant’ way by confirming that altering the balance of gut bacteria can promote inflammatory responses and the development of metabolic syndrome.
“We showed that the altered bacterial population is more aggressive in infiltrating the host and producing substances, namely flagellin and lipopolysaccharide, that further promote inflammation,” explained senior researcher Professor Andrew Gewirtz of at Georgia State University.
"These results suggest that developing a means to promote a more healthy microbiota can treat or prevent metabolic disease," he said. "They confirm the concept that altered microbiota can promote low-grade inflammation and metabolic syndrome and advance the underlying mechanism.”
Microbiome malady
The gut microbiota plays a vital role in health, and can promote chronic inflammatory diseases such as Crohn's disease and ulcerative colitis when it becomes dysregulated. In addition, the team suggest that an altered gut microbiota promotes inflammation that leads to metabolic syndrome.
"We've filled in a lot of the details about how it works," sazid Gewirtz. "It's the loss of TLR5 on the epithelium, the cells that line the surface of the intestine and their ability to quickly respond to bacteria.”
“That ability goes away and results in a more aggressive bacterial population that gets closer in and produces substances that drive inflammation."
Gewirtz and his colleagues improved their previous study by comparing mice that were siblings and littermates - making all conditions in the study the same. The mice only differed by whether they were missing a specific gene, TLR5.
Previously, the team had studied mice that were from two different strains and lived in separate environments. In this study, they found the absence of TLR5 on the intestinal surface leads to alterations in bacteria that drive inflammation, leading to metabolic syndrome.
The authors noted that gut bacteria are normally found in the mucous layer at a certain distance away from epithelial cells. However, the findings show that an altered gut microbiota is more aggressive in infiltrating the host and gets very close to the epithelium.
This altered population produces flagellin and lipopolysaccharide, which further promote inflammation.